The volume of the tank on your A8 Limousine is 17L.
When the remaining AdBlue® mileage reaches 1500 miles, a warning light appears on the dashboard. An audio signal sounds to warn you. Below 650 miles an AdBlue® warning is displayed on the dashboard, an alarm signal sounds and a message warns you that restarting the car is impossible once the tank is empty. When the tank is empty, a message is displayed and three audio signals echo. To switch the AdBlue® warning off when the tank is empty, pour at least 5,7L of AdBlue® in the tank.
When your warning reaches 0 miles, restarting your car is not possible anymore once the engine is turned off. If your engine is till running, you can drive to the next service station. If the car does immediately start, you need to wait for two minutes for the system to detect the AdBlue®top up. If the tank of AdBlue® is empty, you need to turn the ignition on for around 15 seconds and then start the engine.
This information can vary on some vehicles of the same model in relation to the options chosen by the manufacturer.